This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Pdu microcompartment is a proteinaceous, subcellular structure that serves as an organelle for the metabolism of 1,2-propanediol in /Salmonella enterica/. It encapsulates several related enzymes within a shell composed of a few thousand protein subunits. Recent structural studies on the carboxysome, a related microcompartment involved in CO_2 fixation, have concluded that the major shell proteins from that microcompartment form hexamers that pack into layers comprising the facets of the shell. The goal of these subproject is to elucidate the structure of proteins that form of the Pdu microcompartment.